An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without a human pilot on-board. Its flight is either controlled autonomously by computers in the vehicle, or under the remote control of a navigator. An UAV has a navigation device on-board in order to be able to determine its position, which is important not only for autonomously controlled flights, but also for remote controlled flights since the navigator requires for flight control the actual position of an UAV.
If the navigation device on-board is not working properly and causes positioning errors, the UAV is out of control, and will not be able to fulfil its mission. The malfunction of the navigation device can be caused either by internal damage or by external interference. External interference can be intentionally or unintentionally caused. Intentional interference is usually caused by jammers, which are devices that interfere reception of radio signals such as GNSS (Global Navigation Satellite System) signals for positioning.